Various X-ray generating devices are known from the prior art. In a known device, X-ray are generated by directing electrons, emitted by a cathode, onto an anode, the anode emitting the X-rays as a result of receiving the electrons from the cathode. In the known device, a vacuum separates the cathode and anode.
A lot of research has been done to provide the device with a suitable electron emitting cathode. For example, it is known to apply carbon-nanotubes to the X-ray apparatus, see for example US 2003/0142790A1 or US2004/0114721A1, to emit the electrons by field emission. Besides, it is known to apply arrays of lithographically manufactured sharp cones to emit the electrons. In such devices, generally, electrons are being emitted directly from sharp tips or edges into a vacuum due to an electrical field, to be attracted by the anode. Also, in such devices, the emission of the electrons can be achieved at a relatively low temperature.
However, such known X-ray generator devices are relatively expensive and complex, and generally take relatively many different manufacturing steps to produce.